Which is cheaper, a coil or TPS? Replace that one first.

 

TPS here I come.

Got on the highway tonight and the fuel cut still happens. Swore it was the VSS... guess not. More to come!

Justin

 

At this point you seriously need a knowledgeable,competent, skilledor experiencemechanic to diagnose your problem.Stop throwing money into parts swapping.

If you have a volt meter and know how to use it, try this before replacing your TPS. Most TPS has three wires going into the TPS harness. One wire is ground, one wire is a 5v reference signal and the other is the signal wire back to the ECM.

[ul][*]With the ignition on, use a paper clip to back probe each wire that goes into the TPS harness (keep the harness connected to the TPS)[*]The 5v reference signal will usually be anywhere from 4.5v to 5v[*]The ground wire will be exactly that. No voltage, just ground.[*]The voltage on the signal will usually be under 1v andwill vary with throttle position.[*]Once you have determine which wire is the signal wire, have someone slowly press on the gas pedal.[*]The signal voltage should slowly increase as they press more on the pedal.[*]Once at full throttle, the signal wirevoltage should be simalar to the 5v reference voltage.[*]The key is to see the voltage continueincrease as the pedal is depress.[*]Any voltage spike or irregular voltage on the signal wiremight indicate a bad TPS.[/ul]
I can't remember, did you say you already tried installing your old MAF sensor with no luck?

 

I hear ya Mike - the biggest problem is there aren't any decent Land Rover mechs in the area. I'm not really concerned about the money; at least not a little here and there for the stuff is most common to have problems. Sensor here, sensor there... But I do have a limit.

I guess the biggest issue is the codes are so generic. Misfire on 8, misfire on 4, misfire on 7, and multiple misfires. Could be a number of things and I'm just replacing the more obvious - you know, stuff that at 100K is likely to need replacing.

Anyway - I do have a volt meter and will look at the TPS. Thanks for the tips.

I remember when I first rebuilt my rx7... I couldn't get the damn thing to run. The primary injectors just wouldn't fire under load. They ohm'd out fine, opened with a 9v battery, etc etc etc... nothing worked. Then one day I was messing around and installed a second ground from the battery and bingo. Car ran.

Justin

EDIT - No, I haven't messed with the MAF at all.

 

I disagree with the termalogy "Land Rover mechanic". 90% of these trucks areno different that manyother vehicles out there. I've never worked on a LR before, but Ican hold my own on this truck and any other vehiclesthat's new to me.So saying you need a Land Rover mechanic,I disagree. Needing a competent mechanic, that I agree with.

As you know, before diagnosing any driveability problem you have to make sure all your fundementals are covered.Fuel, ignition and mechanical. Which Wankel's have you rebuilt, 12A or 13B? Since you're having mis-fire codes I would concentrate more on the ignition system and donot think for one second components can't go bad with 5000 miles.

 

I guess I missed that the first time, if you have mis fires you need new plug wires. And maybe new plugs.
Remove your plugs and see if any are fouled and then let us know.
What brand of plug wires did you use?

 

Ok, I have tried to re-read this post. Anyone thought about valves? If you are running rich and have been for a long time, it is wry possible that one of your valves is sticking. Do an induction cleaning if you haven't done one. Drive the truck in 2nd gear and see what RPM the hesitation happens, or if it is all of the time.

 

Mike - agreed. The reason I said Land Rover mechanic is because many of the regular shops in the area won't get near the truck simply because of the name. You're right - pretty much no different than any other vehicle. As for the Wankels, they were all 13bREW. Before the 350z I had a 94FD with a T78 single turbo and all the goodies. Very fun car! As for the rover, thanks for the advise thus far. I think it's ignition related as well.. we'll see!

Spike - Brand new Magnecor 8mm and new plugs as well. When I replaced the plugs, the rich mixture was obvious. I was thinking coils earlier only because I know the wires and plugs are good. Will check the plugs again and report back. Thanks!

okdisko - thanks. I have done the induction; twice. Just wanted to be sure since the first time I didn't let the seafoam sit very long... maybe 10 minutes. So I did it again. It DID help. As for the hesitation, it's MUCH MORE evident in DRIVE. Because the tranny shifts at such low RPMS, it stumbles like crazy. When I manually drive it, the hesitation is much less noticeable, and only around 1800-2300RPM. After that it smooths out. If I really hammer on it, there is an additional kick (almost like VTEC in Hondas) at around 32-3300. Almost seems as if a coil fires up or an injector opens. But I don't beat on it much past that of course.

Thanks for all the help guys, it is seriously appreciated. Hopefully I can return the favor sometime.


Justin

98DI
106K

 

BUMP so Original Poster can see the info...

Justin

 

Justin.

It sound frightenly like the problem I have with my 1998 Disco. Although mine stalls and sputters for ~10min each AM until it gets up to temp. Then it suddenly runs just fine. I recently replaced my sparkplug wires with Magnacore 8mm. But no difference. You may want to try the temperature sensor and the throttle position sensor. NAPA has each for under $50.00. I replaced each of mine but no luck. I still think the probelm is related to the temp sensor. I have had the samemechanic troublesas you - crummy mechanics in my area and many won't touch a Land Rover.2 mechanics have just said they can not figure it out. I just get the "random Misfire" codes just like you....

Hang in there.. My original thread is enclosed. I hope someone has ideas. I also replaced my coilpack but that clearly wasn't the problem. So - I now have an extracoilpack for a 1998 Disc for sale (cheap) if you want to swap yours out.

Peter (pedro.malo2121@yahoo.com)




https://landroverforums.com/m_65695/tm.htm

________________________________________

Have a 98 Disco 1 with 75k miles. Normally runs great. A few months back after sitting for a week in an airport garage, it started sputtering, chugging and running like the Catalytic Convertor was completely jacked or the timing was way off.

Had it towed to a shop ( a seasoned rover mechanic) found to have codes for a bad camshaft and crankshaft sensors - both were replaced.

Problem disappeared, for a while.....

Back in shop again. No code errors, the poor running problem doesn't always happen - only sometimes (usually when my need for the truck is pressing)

My mechanic replaced the timing chain, and tested known good ECM, Air Flow Meter and Catalytic Convertor. Yet the problem remains, it seems to get worse (poor running, chugging, missing, it sounds and feels exhaust related) when placing load on engine or fast starts. Some days it runs just fine, on other days it is undriveable and can not accelerate over 25mph and sounds bloody aweful.

Any ideas? We've tested or replaced the following items:

ECM, Convertor, Air Flow Meter, Timing Chain, Crank Shaft Sensor, Camshaft Sensor.


Could this be water related? It seems to be worse when it rains. Which is kinda crazy.
Thanks - Peter